Advances in technology have resulted in an increasing demand for system-on-chip products where both analog and digital signal processing are desirable. For example analog circuits capture an analog signal from the surrounding environment and transform the signal into bits which are then transformed into signals for driving digital circuitry and output functions. Increasingly it is advantageous to have both the analog circuitry and digital circuitry in close proximity, for example in the form digital blocks and analog blocks of circuitry which function together to implement the function of the system, also referred to as mixed mode systems.
For example, passive components (inductors, resistors, and capacitors) in analog/mixed-signal design are used for a wide variety of functions including tuning, filtering, impedance matching, and gain control. For example, MOM capacitors are critical in several mixed signal integrated circuits such as analog frequency tuning circuits, switched capacitor circuits, filters, resonators, up-conversion and down-conversion mixers, and A/D converters.
In metal-oxide-metal (MOM) structures, which are included in analog circuitry building blocks, capacitors with a relatively large capacitance are frequently desirable. MOM structures of the prior art generally achieve a higher level of capacitance by inter-digitated metal line electrodes to achieve capacitors wired in parallel in a particular metallization level.
For example, the MOM capacitor structures of the prior art have relied on metal line electrodes formed in staked metallization levels where the metallization levels are interconnected between metallization layers by metal vias.
Problems in the prior art include the large number of stacked metallization layers and associated interconnecting vias to achieve a desired level of capacitance, thereby utilizing valuable semiconductor area and volume.
There is therefore a need in the semiconductor device processing art for improved MOM capacitor structures and manufacturing processes to achieve a higher capacitance value while minimizing the size of the MOM structure and achieving the same in a cost effective manner.
It is therefore an object of the invention to provide an improved MOM capacitor structure and manufacturing process to achieve a higher capacitance value while minimizing the size of the MOM structure, in addition to overcoming other deficiencies and shortcomings of the prior art.